Classifications

• • C—CHEMISTRY; METALLURGY
  • C25—ELECTROLYTIC OR ELECTROPHORETIC PROCESSES; APPARATUS THEREFOR
  • C25D—PROCESSES FOR THE ELECTROLYTIC OR ELECTROPHORETIC PRODUCTION OF COATINGS; ELECTROFORMING; APPARATUS THEREFOR
  • C25D3/00—Electroplating: Baths therefor
  • C25D3/02—Electroplating: Baths therefor from solutions
  • C25D3/56—Electroplating: Baths therefor from solutions of alloys
  • C25D3/565—Electroplating: Baths therefor from solutions of alloys containing more than 50% by weight of zinc
• • C—CHEMISTRY; METALLURGY
  • C25—ELECTROLYTIC OR ELECTROPHORETIC PROCESSES; APPARATUS THEREFOR
  • C25D—PROCESSES FOR THE ELECTROLYTIC OR ELECTROPHORETIC PRODUCTION OF COATINGS; ELECTROFORMING; APPARATUS THEREFOR
  • C25D5/00—Electroplating characterised by the process; Pretreatment or after-treatment of workpieces
  • C25D5/10—Electroplating with more than one layer of the same or of different metals
• • C—CHEMISTRY; METALLURGY
  • C25—ELECTROLYTIC OR ELECTROPHORETIC PROCESSES; APPARATUS THEREFOR
  • C25D—PROCESSES FOR THE ELECTROLYTIC OR ELECTROPHORETIC PRODUCTION OF COATINGS; ELECTROFORMING; APPARATUS THEREFOR
  • C25D5/00—Electroplating characterised by the process; Pretreatment or after-treatment of workpieces
  • C25D5/60—Electroplating characterised by the structure or texture of the layers
  • C25D5/605—Surface topography of the layers, e.g. rough, dendritic or nodular layers
• • H—ELECTRICITY
  • H05—ELECTRIC TECHNIQUES NOT OTHERWISE PROVIDED FOR
  • H05K—PRINTED CIRCUITS; CASINGS OR CONSTRUCTIONAL DETAILS OF ELECTRIC APPARATUS; MANUFACTURE OF ASSEMBLAGES OF ELECTRICAL COMPONENTS
  • H05K3/00—Apparatus or processes for manufacturing printed circuits
  • H05K3/38—Improvement of the adhesion between the insulating substrate and the metal
  • H05K3/382—Improvement of the adhesion between the insulating substrate and the metal by special treatment of the metal
  • H05K3/384—Improvement of the adhesion between the insulating substrate and the metal by special treatment of the metal by plating
• • H—ELECTRICITY
  • H05—ELECTRIC TECHNIQUES NOT OTHERWISE PROVIDED FOR
  • H05K—PRINTED CIRCUITS; CASINGS OR CONSTRUCTIONAL DETAILS OF ELECTRIC APPARATUS; MANUFACTURE OF ASSEMBLAGES OF ELECTRICAL COMPONENTS
  • H05K2201/00—Indexing scheme relating to printed circuits covered by H05K1/00
  • H05K2201/03—Conductive materials
  • H05K2201/0332—Structure of the conductor
  • H05K2201/0335—Layered conductors or foils
  • H05K2201/0355—Metal foils
• • H—ELECTRICITY
  • H05—ELECTRIC TECHNIQUES NOT OTHERWISE PROVIDED FOR
  • H05K—PRINTED CIRCUITS; CASINGS OR CONSTRUCTIONAL DETAILS OF ELECTRIC APPARATUS; MANUFACTURE OF ASSEMBLAGES OF ELECTRICAL COMPONENTS
  • H05K2203/00—Indexing scheme relating to apparatus or processes for manufacturing printed circuits covered by H05K3/00
  • H05K2203/03—Metal processing
  • H05K2203/0307—Providing micro- or nanometer scale roughness on a metal surface, e.g. by plating of nodules or dendrites
• • H—ELECTRICITY
  • H05—ELECTRIC TECHNIQUES NOT OTHERWISE PROVIDED FOR
  • H05K—PRINTED CIRCUITS; CASINGS OR CONSTRUCTIONAL DETAILS OF ELECTRIC APPARATUS; MANUFACTURE OF ASSEMBLAGES OF ELECTRICAL COMPONENTS
  • H05K2203/00—Indexing scheme relating to apparatus or processes for manufacturing printed circuits covered by H05K3/00
  • H05K2203/07—Treatments involving liquids, e.g. plating, rinsing
  • H05K2203/0703—Plating
  • H05K2203/0723—Electroplating, e.g. finish plating
• • Y—GENERAL TAGGING OF NEW TECHNOLOGICAL DEVELOPMENTS; GENERAL TAGGING OF CROSS-SECTIONAL TECHNOLOGIES SPANNING OVER SEVERAL SECTIONS OF THE IPC; TECHNICAL SUBJECTS COVERED BY FORMER USPC CROSS-REFERENCE ART COLLECTIONS [XRACs] AND DIGESTS
  • Y10—TECHNICAL SUBJECTS COVERED BY FORMER USPC
  • Y10T—TECHNICAL SUBJECTS COVERED BY FORMER US CLASSIFICATION
  • Y10T428/00—Stock material or miscellaneous articles
  • Y10T428/12—All metal or with adjacent metals
  • Y10T428/12493—Composite; i.e., plural, adjacent, spatially distinct metal components [e.g., layers, joint, etc.]
  • Y10T428/12535—Composite; i.e., plural, adjacent, spatially distinct metal components [e.g., layers, joint, etc.] with additional, spatially distinct nonmetal component
  • Y10T428/12556—Organic component
  • Y10T428/12569—Synthetic resin
• • Y—GENERAL TAGGING OF NEW TECHNOLOGICAL DEVELOPMENTS; GENERAL TAGGING OF CROSS-SECTIONAL TECHNOLOGIES SPANNING OVER SEVERAL SECTIONS OF THE IPC; TECHNICAL SUBJECTS COVERED BY FORMER USPC CROSS-REFERENCE ART COLLECTIONS [XRACs] AND DIGESTS
  • Y10—TECHNICAL SUBJECTS COVERED BY FORMER USPC
  • Y10T—TECHNICAL SUBJECTS COVERED BY FORMER US CLASSIFICATION
  • Y10T428/00—Stock material or miscellaneous articles
  • Y10T428/12—All metal or with adjacent metals
  • Y10T428/12493—Composite; i.e., plural, adjacent, spatially distinct metal components [e.g., layers, joint, etc.]
  • Y10T428/12639—Adjacent, identical composition, components
  • Y10T428/12646—Group VIII or IB metal-base
• • Y—GENERAL TAGGING OF NEW TECHNOLOGICAL DEVELOPMENTS; GENERAL TAGGING OF CROSS-SECTIONAL TECHNOLOGIES SPANNING OVER SEVERAL SECTIONS OF THE IPC; TECHNICAL SUBJECTS COVERED BY FORMER USPC CROSS-REFERENCE ART COLLECTIONS [XRACs] AND DIGESTS
  • Y10—TECHNICAL SUBJECTS COVERED BY FORMER USPC
  • Y10T—TECHNICAL SUBJECTS COVERED BY FORMER US CLASSIFICATION
  • Y10T428/00—Stock material or miscellaneous articles
  • Y10T428/12—All metal or with adjacent metals
  • Y10T428/12493—Composite; i.e., plural, adjacent, spatially distinct metal components [e.g., layers, joint, etc.]
  • Y10T428/12771—Transition metal-base component
  • Y10T428/12785—Group IIB metal-base component
  • Y10T428/12792—Zn-base component
• • Y—GENERAL TAGGING OF NEW TECHNOLOGICAL DEVELOPMENTS; GENERAL TAGGING OF CROSS-SECTIONAL TECHNOLOGIES SPANNING OVER SEVERAL SECTIONS OF THE IPC; TECHNICAL SUBJECTS COVERED BY FORMER USPC CROSS-REFERENCE ART COLLECTIONS [XRACs] AND DIGESTS
  • Y10—TECHNICAL SUBJECTS COVERED BY FORMER USPC
  • Y10T—TECHNICAL SUBJECTS COVERED BY FORMER US CLASSIFICATION
  • Y10T428/00—Stock material or miscellaneous articles
  • Y10T428/12—All metal or with adjacent metals
  • Y10T428/12493—Composite; i.e., plural, adjacent, spatially distinct metal components [e.g., layers, joint, etc.]
  • Y10T428/12771—Transition metal-base component
  • Y10T428/12861—Group VIII or IB metal-base component
  • Y10T428/12903—Cu-base component
  • Y10T428/1291—Next to Co-, Cu-, or Ni-base component
• • Y—GENERAL TAGGING OF NEW TECHNOLOGICAL DEVELOPMENTS; GENERAL TAGGING OF CROSS-SECTIONAL TECHNOLOGIES SPANNING OVER SEVERAL SECTIONS OF THE IPC; TECHNICAL SUBJECTS COVERED BY FORMER USPC CROSS-REFERENCE ART COLLECTIONS [XRACs] AND DIGESTS
  • Y10—TECHNICAL SUBJECTS COVERED BY FORMER USPC
  • Y10T—TECHNICAL SUBJECTS COVERED BY FORMER US CLASSIFICATION
  • Y10T428/00—Stock material or miscellaneous articles
  • Y10T428/12—All metal or with adjacent metals
  • Y10T428/12493—Composite; i.e., plural, adjacent, spatially distinct metal components [e.g., layers, joint, etc.]
  • Y10T428/12986—Adjacent functionally defined components

Definitions

• This invention relates to the treatment of copper foil that is produced to be laminated to form printed circuits.
• it is a treatment that resists undercutting and produces a stable laminate bond under both normal and elevated temperatures.
• this treatment involves a plurality of electrolytic copper treating operations carried out in a plurality of treating tanks, each one being carried out under separate electroplating conditions.
• the first treatment involves the electrodeposition on the copper foil of a nodular powdery copper layer which is coarse and rough and weakly adherent to the base copper foil, followed by a second treatment involving the application of an electrodeposited locking or gilding copper layer which is not nodular in structure but which conforms to the configuration of the first layer.
• the first treatment layer is supplied to increase the bond strength of the copper foil so that it can be more advantageously bonded to a substrate to form a laminate for use in electronic printed circuits.
• This first treatment step is capable of increasing the bond strength of one-ounce foil to range from 10 to 11 pounds per inch of width of laminate, depending upon the particular conditions utilized in this first treatment step.
• 2 sshhoouullid be about 3-5 and preferably about 4 gms./m of foil.
• the second treatment step that is, the application of the "locking" or “gilding" copper layer, does not reduce the bond strength supplied by the initial copper layer treatment, and ordinarily will increase such bond strength to about 12-13 lbs./In. of width of laminate. It does, however, reduce or eliminate the disadvantageous powder transfer characteristics which the foil otherwise would have as a result of the first treatment stage.
• the layer deposited in this second treatment stage should have a thickness such that this layer causes substantially no decrease in bond strength. For best results, the amount of copper deposited in this second step to achieve this
• undercutting is the removal of the material under some or all of the foil that is protected by the photoresist that is applied to define the printed circuit. Removal of copper under the photoresist weakens bonding of the copper to the board. In extreme cases of undercutting, portions of the printed circuit may even become detached from the board. It is therefore necessary that the substances used to produce the gilding layer and the barrier layer withstand the etchant sufficiently to produce an acceptable amount of undercutting. Details of the processes described above are given in U. S. Patent No. 3.857.681. "Copper Foil Treatment And Products Produced Therefrom. " which is incorporated here by reference as if set forth fully.
• An improved treatment for copper foil that is to be used for lamination to a board comprises electrodepositing a dendritic layer of copper on the side of the foil that is to be laminated to the board.
• the dendritic layer is secured by electrodepositing a gilding layer of copper over it.
• a barrier layer is next electrodeposited over the gilding layer.
• the barrier layer is formed by means such as electrodeposition from a solution containing ions of zinc, nickel and antimony. This in turn is covered with an anticorrosion layer that is formed of chromates or phosphates, disposed over the barrier layer.
• the present invention comprises applying a plurality of steps in the treatment of copper foil to produce a laminated circuit board with excellent bonding strength, good etchability in all commonly used etchants, resistance to staining, resistance to undercutting, and resistance to tarnishing.
• the invention can be practiced either with electrolytically deposited copper foil or with mechanically produced copper foil. In the latter case, the laminate bond tends to be significantly weaker.
• Electrolytically deposited copper foil has the advantage of having a matte surface and a shiny surface.
• the first step in treatment is to produce a dendritic layer of materials by electrodeposition on the matte surface. Copper is a preferred material for the dendritic layer.
• the dendritic layer is then gilded by electrodeposition of a layer of a material such as copper to secure the dendrites.
• the foil after the gilding process is next treated to form a barrier layer. This is preferably done by electroplating in a bath that contains ionic zinc, nickel and antimony. Several examples follow of conditions that have been used for electrodepositing a barrier layer.
• EXAMPLE 1 The matte side of a sam le of copper foil that has been treated to grow a dendritic layer which was then gilded was subjected to the following conditions for electrodeposition. A surface current density of 40 amperes per square foot was applied from an insoluble anode to the matte surface of the foil as a cathode. The current was passed through a solution that included the following constituents.
• Temperature of the plating solution was maintained at approximately 27°C and the pH of the solution was maintained at approximately 2.0 by the addition of zinc oxide or sulphuric acid.
• the plating time was about 10 seconds.
• EXAMPLE 2 The matte side of a sample of copper foil that has been treated to grow a dendritic layer which was then gilded was subjected to the following conditions for electrodeposition. A surface current density of 80 amperes per square foot was applied from an insoluble anode to the matte surface of the foil as a cathode. The current was passed through a solution that included the following constituents. -Zinc as sulphate: concentration 50 grams per liter, -Nickel as sulphate: concentration 20 grams per liter.
• -Antimony as potassium antimony tartrate concentration 1000 parts per million. Temperature of the plating solution was maintained at approximately 27°C and the pH of the solution was maintained at about 2.0 by the addition of zinc oxide or sulphuric acid.. The plating time was about 10 seconds. Successful results have been achieved by forming barrier layers with constituents and quantities over the ranges listed in Example 3.
• EXAMPLE 3 -Zinc as sulphate: from 20-100 grams per liter. -Nickel as sulphate: 1-70 grams per liter. -Antimony as potassium antimony tartrate: 600-1800 parts per million.
• Nickel-zinc-antimony 0.47 0.46 It can be seen from the table that a barrier layer of nickel, zinc, and antimony resists undercutting more than the barrier layers formed of nickel and zinc or of zinc and antimony.
• the final step in preparing copper foil for bonding to a prepreg comprises applying a coating that reduces tarnishing. This is typically accomplished by electroplating in a bath containing chromates. phosphates. or both. Typical examples are shown in U. S. Patent No. 3.625.844, entitled “Stainproofing Process And Products Resulting Therefrom," and U. S. Patent No. 3. 853,716, entitled “Electrolytic Copper Stainproofing Process,” which is incorporated here by reference as if set forth fully. Use of this or any other of the well-known processes for reducing tarnishing, together with the process of the present invention to provide a better barrier layer, results in an improved copper foil.

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• Chemical & Material Sciences (AREA)
• Engineering & Computer Science (AREA)
• Organic Chemistry (AREA)
• Electrochemistry (AREA)
• Materials Engineering (AREA)
• Metallurgy (AREA)
• Chemical Kinetics & Catalysis (AREA)
• Manufacturing & Machinery (AREA)
• Microelectronics & Electronic Packaging (AREA)
• Electroplating Methods And Accessories (AREA)
• Laminated Bodies (AREA)
• Parts Printed On Printed Circuit Boards (AREA)
• Manufacturing Of Printed Wiring (AREA)

Priority Applications (2)

Applications Claiming Priority (2)

Publications (1)

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Family Applications (1)

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Cited By (3)

Families Citing this family (34)

Citations (4)

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• 1985
  • 1985-06-28 US US06/750,111 patent/US4572768A/en not_active Expired - Lifetime
• 1986
  • 1986-06-26 CA CA000512542A patent/CA1277948C/en not_active Expired - Lifetime
  • 1986-06-27 DE DE8686904606T patent/DE3675356D1/de not_active Expired - Fee Related
  • 1986-06-27 JP JP61503587A patent/JPH0665757B2/ja not_active Expired - Fee Related
  • 1986-06-27 EP EP86904606A patent/EP0227820B1/de not_active Expired - Lifetime
  • 1986-06-27 WO PCT/US1986/001396 patent/WO1987000212A1/en active IP Right Grant

Patent Citations (4)

Non-Patent Citations (1)

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